The present invention relates to apparatus for comminuting fibrous material, especially tobacco, and more particularly to improvements in conveyors which can be used in apparatus for shredding tobacco leaves or the like to compact tobacco and to advance compacted tobacco into the range of one or more orbiting knives forming part of a comminuting device.
A tobacco shredding apparatus normally comprises a comminuting device including a rotary drum-shaped carrier for orbiting knives and a system of convergent chains which advance tobacco leaves into the range of the knife or knives. As a rule, the chains define a chamber whose height decreases in the direction of tobacco transport so that the leaves which are fed into the inlet of the chamber are compacted and form a continuous cake not later than when they reach the outlet of the chamber. The links of conventional chains normally consist of drawn corrosion-resistant metal and resemble plates which are pivotally connected to each other by pintles or the like. Chains which employ such plate-like hingedly-connected links must be provided or used with specially designed auxiliary devices which prevent penetration of portions of tobacco leaves and/or tobacco juice and/or other adhesive liquid or water-soluble ingredients of tobacco. Penetration of tobacco leaves and/or liquid ingredients of tobacco into the spaces between neighboring plate-like links of conventional chains is highly undesirable, not only when the tobacco leaves do not contain or carry any casing but especially when the leaves are contacted with casing prior to introduction into the shredding apparatus. The casing tends to adhere to and to accumulate on component parts of the chains so that the links are likely to jam, i.e., they cannot pivot or pivot only within limits relative to each other. The resulting greatly increased friction can be overcome only by resorting to powerful prime movers whose energy requirements are excessive as well as to frequent cleaning of links.
Certain proposals to improve the construction of link chains which are used for the compacting and transport of tobacco in shredding and analogous comminuting apparatus are disclosed in German Pat. No. 1,183,014. This patent proposes to employ chains having several types of links and to provide sealing elements in the form of strips or the like. Such chains are complex and expensive; furthermore, they cannot satisfactorily prevent escape of tobacco juice and/or blocking of links by accumulations of casing and/or portions of tobacco leaves.